简介：Themercurycontentin158fishesand28musselsintheSecondSonghuariverweredetected.Therangeofmercuryconcentrationsinfishesandmusselswas0.02-0.66mg/kgand0.002-0.056mg/kg,respectively.Thehistorychangeofmercurycontentinfisheswasanalyzedinthispaper.Fromupstreamtodownstream,theaveragemercuryconcentrationsinfishesincreasedwiththeincreaseofthedistancetotheheadstream,thendecreasedinthedownstreamofWujiazhantown(samplingsite).Thefactilluminatedthatthesourceofmercurycontaminationwasmercuryinsediment.Inthedifferentspeciesoffishes,themercuryconcentrationinParasiburusasvtuswasthehighestandtheorderofmercurydistributioninfisheswas:themercuryvalueinfishesintheriverbottom>thatinfishesinthesurfaceandthatinpredaciousfishes>thatinherbivorousfishes.Intheinvestigation,therewereamountoffisheswhosemercuryvalueexceededthecriterionforthatinfishesthatsuggestedthatthemercurycontaminationintheSecondSonghuaRiverhavenotcompletelybeeneliminateduntilnow.

简介：Beijing,Sep.10-13,2002Organizedby:TsinghuaUniversityofChina&InternationalResearchandTrainingCenteronErosionandSedimentation(IRTCES)Sponsoredby:NationalNaturalScienceFoundationofChina(NSFC)InternationalAssociationforHydraulicResearch(IAHR)UnitedNationsEducational,ScientificandCulturalOrganization(UNESCO)InternationalAssociationofHydrologicalSciences(IAHS)KasselUniversityofGermanyChineseHydraulicEngineeringSociety(CHES)German-SinoUnsteadySedimentTransport(GESINOS)http://vww.irtces.orghttp://www.Tsinghua.edu.cnINTRODUCTIONInthepastdecadefrequentlyoccurringfloodsclaimedthousandsoflivesandcausedeconomiclossofbillionsofUSdollars.AmongthemtheMississippiRiverfloodin1993,theRhineRiverfloodin1995,theYangtzeRiverfloodin1998,theHaiheRiverfloodin1996,andthestormsurgesinBangladeshin1991arethemostdevastating.Itisevidentthatboththefrequencyandintensityoffloodingareincreasing.TheDirstInternationalSymposiumonFloodDefenceinSep.2000,initiatedbyProfs.ToensmannandKoch,attractedmorethan200scientistsandengineersgatheringinKasselUniversitydiscussingtheever-increasingconcernedproblemsandsharingexperiencesandstrategiesforflooddefence.ManyscientistssuggestedtocontinuethetechnicalforumandtheTsinghuaUniversity(oneofthetopuniversitiesofChina)andtheInternationalResearchandTrainingCenteronErosionandSedimentation(IRTCES)areorganizingtheSecondInternationalSymposiumonFloodDefence(ISFD'2002)scheduledonSep.10-13,2002.Thepurposeoftheconferenceistoreviewthestate-of-the-artofthestudiesonfloodingandengineeringandnon-engineeringstrategies.Thesymposiumwillfocusonabetterunderstandinglawsoffloodingandenvironmentalproblemsinvolved,differentperspectivesevolved,climatechangeanditsimpactonextremehydrologicalevents,andreportingnewapproachestothestudyandcontroloffloodstrategies.More